Digital video signals are prevalent in digital television, set-top, portable consumer video equipment such as camcorder, video production, and video distribution systems. These digital video signals generally consist of video clock, video data, and corresponding video synchronization information. Sometimes, ancillary data also is included during video blanking time. The transfer of such data from one electronic device to another usually involves a synchronous transfer on a parallel or serial bus using the video clock. Often, more than one signal is transmitted at the same time.
In traditional video systems, parallel video signals are transmitted in the system using a format such as the digital data stream shown in FIG. 1A. The digital data stream 101 can contain video data, synchronization data (e.g. EAV/SAV,) and ancillary data. A data clock 103 is used. One clock edge, usually the rising edge, is synchronized with the data. If the data rate of video signal is the same as the video pixel rate, than the data clock usually is referred to as the pixel clock. This scheme has been used by the Society of Motion Picture Engineers in standards SMPTE-274M, SMPTE-295M, SMPTE-125M, etc. These standards cover various common video resolutions and synchronization schemes in use, but the same transmission technique can be applied to non-standard video signals. In systems with multiple video signal sources, each video signal is transmitted on a separate video bus. The multiple video buses add expense to the system.